Differentiation therapy of myelodysplastic syndromes with retinoic acid

Clinical trials of differentiation therapy on MDS with retinoic acid are reviewed, and it is discussed whether the differentiation therapy with this drug has scientific relevance for MDS. 13-Cis retinoic acid (13-CRA) may have moderate effect on 20-30% of patients with MDS. In general, the responses are short and toxicity is significant. Since the responses may take at least three weeks and sometimes several months to occur, only patients with a relatively indolent clinical course of MDS would be suitable candidates for this therapy. However, a placebo-controlled prospective randomized study could not confirm the effectiveness of this retinoic acid on MDS. There are only a few clinical trials of all-trans retinoic acid (ATRA) for treatment of MDS. ATRA may have a moderate effect on MDS, but no such a remarkable effect shown on acute promyelocytic leukemia. A placebo-controlled randomized study as having been conducted in 13-CRA is definitely needed to confirm the effectiveness of ATRA on MDS.